Definition
A reduction in a person's normal physical, mental, or sensory capabilities that degrades their ability to safely operate or work around an aircraft. Common causes include fatigue, illness, medication, alcohol, drugs, dehydration, hypoxia, stress, and emotional upset.
Plain English
Anything that makes a pilot less sharp, slower to react, or less able to think clearly than they normally would be.
Context Anchor
Seen in aeromedical, human factors, alcohol and drug, fatigue, and fitness-for-flight discussions.
Derivation
From the Old French 'empeirer,' meaning to make worse. The aviation use keeps that core idea: the pilot is in a worse condition than their normal baseline, even if they still feel functional.
Why Pilots Care
Flying while impaired violates regulations and raises accident risk, so pilots must self-assess before every flight.
Intuition Check
Impairment does not only mean being drunk or obviously unable to function. In aviation, a tired, sick, medicated, injured, or oxygen-starved pilot may also be impaired.
Example Sentence 1
After taking a new prescription medication, the pilot grounded himself for 48 hours to avoid any risk of impairment.
Example Sentence 2
Even mild fatigue can produce impairment that affects reaction time during landing.